Governor



Ma? 5 1942 IM. J. DI 'roR GGVERNOR Filed Dec. 28,. 1939 l I Gttomeg- Patented May 5, 1942 UNITED STATES PATENT OFFICE GOVERNOR Application December 28, 1939, Serial No.y 311,326

Claims.

This invention relates to improvements in centrifugal governors, and more particularly to such improvements as will render the governors more stable and dependable and yet more sensitive in their governing action.

Centrifugal governors comprise fiyweights which are commonly biased inwardly and thrown out by centrifugal force against their biasing. The flyweight's are usually directly mounted on at or leaf springs which provide the biasing for the weights. These springs are placed in relation to the shaft of the governor so that the direction of their mode of motion of greatest flexibilityi. e., in ythe case of at springs the first mode of motion in bending-will be radial of the shaft which carries the governor, thereby permitting the flyweights to move principally in translation in the 'direction of the vcentrifugal force acting thereon. Flat springs have, however, various modes of motion or vibration other than the first mode of motion in bending just mentioned; these modes of motion, which are detrimental to the operation of the governor, comprise torsional motion (i. e., motion of the spring about and perpendicular to its longitudinal axis) and the higher modes of motion in bending. Considerable flexibility of the springs in the direction `of its first mode of motion in bending is necessary to permit a sensitive governing action; on the other hand, a high degree of stiffness against motion of the springs in torsion and at thek higher modes of motion in bending is highly important in order that' vibrations of the mechanism being governed may not excite undesirable modes of motion or resonances in the governor and cause heavy vibration and instable governing action.

It is an object of my invention to provide improved means by which a governor may be rendered stable and dependablel and yet highly sensitive in operation.

Another object is to provide a governor which is well nigh free of undesirable resonances.

Another object is to provide a governor which is insensitive to mechanical vibrations such as may be transmitted to it by the mechanism which it controls.

A further object of my invention is to provide a spring mounting for the flyweight of a governor, which has considerable flexibility in but one mode of motion and a high stiffness against all other modes of motion.

A feature of my invention is to provide a resilient mounting for a flyweight of a centrifugal governor, which comprises a plurality of overlying flat springs spaced from each other and clamped against flexure along a portion thereof at the point of their support and at their point of connection with the yweight.

Further objectsand features of my invention lay in the provision, ina centrifugal governor, of such improved construction and arrangement of parts as 'will fulfill the purposes abovementioned.

Other and allied objects and features of my invention willmore fully appear from the following ldescription and the appended claims.

In thefdescription of my invention reference is had to the accompanying drawing, of which:

Figure 1 is a side elevational view vof a governor appliedto a motor (fractionally` shown) and incorporating my invention;

Figure 2 is a vertical sectional view taken substantially along the line 2-2 of Figure 1;

Figure 3 is a partialfvertical sectional view taken substantially along the line 3-3cf Figure 1; l ,Y

Figure =4is a horizontal sectional view taken substantially along'the line 4-4 of Figure 23;

Figure 5 is an end view of the governor;

Figure 6 is a view inside elevation of an alternative form of'a portion of the governor; and

Figure 7 is a vertical sectional View taken along the line 1--1 of'Figure 6. o

Reference being had to the figures therev will be seen a friction type of centrifugal governor i incorporating-my invention. A friction type lof governor controls the speed of a power source by providing a frictional load on the source which increases ywith an increased speed of the source, and vice versa, about a predetermined speed established by the Ysetting of the governor; such a power source may typically be an electrical motor M rhaving va drive shaft 2 on which the governor may bedirectly mounted, as shown. Although my invention is particularly applicable to, and is. herein illustrated and described in connection with, a friction type of governor, it is to be understood that -no unnecessary limitation of my invention to this type of governor is intended.

A friction type of centrifugal governor may be of the following general construction: On the shaft 2 there are provided two relatively movable members, a collar 3 secured to the shaft by a set screw 4, and a sleeve 5 slidable along the shaft and preferably ccunterbored along its central portion so as to bear on the shaft at its end portions as at 5. Staked tothe sleeve 5 is a disk 6 and interconnecting this disk and the collar 3 are flat springs 'I hereinafter more fully described. Secured `to the springs 1 centrally thereof are i'lyweights 8. These flyweights are thrown outwardly by centrifugal force as the shaft 2 is rotated. As the flyweights are so moved the springs 1 are flexed (i. e., bowed outwardl'y) to cause the sleeve 5 to move along the.-

the centrifugal force action on the lyweightsl 8 will be transmitted at least in part to the friction ring 9 to cause an increase in pressure vbetween the friction ring and its stop, speedin-V creases of ther motor will be counteracted" 'by load increases, and vice versa, so as to stibject.k

the motor to a speed stabilizing influence.

In order to control the speed at which the' governor action begins, the stop I is mounted for adjustment longitudinally of the shaft 2. The mounting for the stop may comprise a short arm I I pinned to one end of a shaft I2 which is journalled in anextension I3 on'fthe frame of the motor, as shown in Figures 2 and 4. Secured to the other end of the shaftY I2 by a set'screw I4 is an arm I5which extends transversely ,ofv the motor. Passing through the ,outer endportion of the arm I5 and threading into; a boss I6 on the frame of the motor is an adjusting screw I1, and interposed between the boss lIIi and arm I5 about'the adjusting screw I1 Tis la compressi'on spring I8. This spring serves to hold the arm I5 against the head of the adjusting screw and also to frictionally hold the "adjusting screw from turning in the boss I6.` However, asdesired, y the adjusting screw may be turned manually to move the stop I0 towards or away from the friction ring 9 solas to control'fthe speedv atv which the governor action beginsi. e., the speed Aat which the friction ring Q' contacts the stop I0.

As heretofore noted, it is highly" important that the flyweights 8 be restricted sov that they may move substantially only in translation as in a direction radial of the shaft 2. yWhen this condition is realized vibrations of the y motor M- such as may be caused by dynamic unbalance of the motor or byv the pulsating nature of the developed torque as in A.y C. motors'f-Pare prethe shaft 2 when they are unflexed-i. e., when the governor is in static condition as shown in Figure 4. In the present instance there are f our flyweights and respective pairs of springs which are disposed at right angle intervals about the shaft 2. The spring pairs are secured along their outer end portions to the collar 3 by screws I9, the collar 3 being provided with four equiangularly spaced ats 3 forming seats forthe respective pairs of springs. The screws I9 pass f through the springs and through spacers between the springs and then thread into the collar, thereby clamping the outer end portions of the springs tightly together in fixed spaced relationshipand holding these portions of the springs securely to the collar. The inner end portions of the spring pairs are also clamped together, against respective spacers 2I, by means of rivets 22, and the spacers 2I are secured to the disk B by screws 23. Securedto the central portion of the spring pairs are the respective fiyweights 8 and interposed between the springs .In the twin-spring mounting structures just described, the flyweights are permitted to move radially outwardly in translation by way of a first mode of motion in bending of the spring' pairs; however, undesirable movements of the' yweights by way of higherv modes of motion in bending and a torsional' jInode of motion are well night prevented. This is because higher" modes of motion in bending occur by way of an angular motion of the Yilyweights about an axis which is perpendicular 'to and in the lmedialr plane of the springs anda torsional Amode of motion-occurs by way of an angular motion of the yweights about an axis which is parallel`I to the longitudinal axis of the springs and inl their medial plane. YThe higher `modes of motion vin bending will thus involve a stretching "and compressing of the springs longitudinally thereof while a torsional mode of motion will involve a sidewise bending of theV springs. Be-A cause of the high degree of stiffness of the springs .in direct tension and of the extremely 4high degree of stiffness-of the springs against y vented from causing undesirable modes ofA vlbration or resonances ofthe flyweights. In accord? is so constructed land arranged as to be flexiblev substantially only in one directionthe direction of its first mode of motion in bending--and to 'be' exceedingly stiff against all modes of motion in other directions. This resilient mounting is in the form of a spring structure comprising a plurality, or a pair as in the present instance, of fiat springs 'I aforementioned; these springs are placed in face-to-face relationship so as to overlie one another, spaced radially in relation to the shaft 2 and clamped in fixed spaced relationship along a substantial portion thereof at the place of their support and at the place where they are connected to the iiyweights 8.

The springs 'I of each pair .are preferablyl clamped at their end portions and mounted so that lthey will be parallel to each' other and to sidewise bending (as because of their considerable width) the spring pairs are rendered exceedingly stiff against these'i undesirable modes.

It is to be understood'that a highly importantk feature of the twin-spring structure as above described resides in the use of a plurality of spaced overlying springsA which are clamped tol gether, in fixed spaced relationship, -along a sub-V not knecessarily restricted to such a mounting as I may also advantageously employ this important feature of my invention lin springstructures'which are mounted in the manner of a cantilever or clamped-free beam, or inthe manner of a free-free beam (i. e., a beam which is unrestricted against torsional motionr at its ends as, forexample, a beam having pivotally supported ends). i Of the undesirable modes of motion the torsional is frequently highly troublesome. To

obtain the maximum ratio of Atorsional .stiffness to bending stiffness of the first mode, so as to subdue torsional vibration of the weights. while vyet not rendering the spring pairs so stiff in their first mode of motion `in bending as to .impede greatly the action of the governor, I find it desirable to employ relatively wide springs which are spaced far apart and made as thin and long as possible; this spacing between the springs is made at least a substantial fractional distance of their width and of the dimension of Athe flyweights in the radial direction of the shaft 2 for example, of the order of one-half or more, of these dimensions., as shown. The spring configuration shown in Figures 1 through 5 represents a practical design wherein these factors have been taken into account while yet maintaining a highly compact form of governor.

Since undesirable modes of motion of the flyweights, as by way of torsional motions and higher modes of motion in bending of the spring structures, are principally angular in character, to keep these undesirable modes of motion at a minimum it is important that the centrifugal forces acting on the flyweights be free of moments which would tend to excite such modes. The. moments on the flyweights will be at a minimum when the iiyweights are symmetrically disposed in relation to the spring structures with the center of gravity of the flyweights in the medial plane of the spring structures. In the embodiment disclosed in Figures 1 through 5 the twin-spring structures are symmetrically disposed in relation to the angular width of the flyweights 8 and the condition of a coincidence of the center of gravity with the medial plane of the twin-spring structures is approximated by causing the twin-spring structures to pass through the inner portion of the flyweights (the spaces 24 being considered as part of the flyweights as heretofore noted.) In this arrangement the twinspring structures are kept close to the shaft 2 so as to reduce the overall size of the governor and yet moments acting on the flyweights are kept at a low value. In certain cases it may, however, be desirable to reduce the moments on the flyweights to a minimum. A construction in which this has been done is shown in Figures 6 and 7; here a spring structure comprising a pair of flat springs, such as the springs l hereinbefore described, is passed symmetrically through and secured to a flyweight 26 which by way of example is shown as block-shaped, the flyweight 26 being slotted as at 2l to permit the springs to pass therethrough and the springs being clamped to the flyweight against blocks 28 by means of the rivets 29. In this construction it is seen that the center of gravity O of the flyweight 26 lies in the medial plane P of the spring structure supporting the flyweight.

The flyweights 8 are preferably made in the shape of sectors which form when the governor is in static condition-i. e. when the springs are unflexed-a cylindrical structure coaxially disposed in relation to the shaft 2. This form of structure presents the maximum weight per unit of circumferential space, thereby enabling the maximum governing actuating force to be obtained for a given size of governor. While this shape of flyweight may in practical construction F require that portions of the weights extend laterally beyond the mounting springs such extensions of the weights are in the present instance prevented from causing torsional vibrations of the weights by reason of the weights being mounted symmetrically in .relation to the vmounting springs with the center of gravity of the weights close to the springs.V

As an expedient in obtaining a highly ysensitive governing action in friction-type governors, itis found important that the coaction between the friction ring 9 and stop I0 be essentially of a non-resilient characterpor if .a resilient effect is here present, that'theresilience or stiffness be high in Vrelation to the' stiffness of the governor as seen by the friction ring. When this condition is realized an increase in governor. speed above that which causes `mere, contact between the friction ring 9 and stop lill will cause the increment of centrifugal force accompanying such speed increase to be almost `wholly transinitted,v in a ratio `determined rby the governor configuration, as a corresponding 'pressure increment between the friction ring and Stopthat is', only a smallpercent'age ofthis force increment on the weight will be lost or taken up by the governor springs, the remaining portion being effective to control the, frictional load on the motor. Such enicient transmission of fthe centrifugal force on the weights into frictional load enables the governor to control the speed of the motor within a very narrow speed range. To obtain a high resilience or stiffness between the friction ring 9 and stop l0 I preferably employ a friction ring made of brake lining and a Stop made of hardened metal.

The governor construction hereinabove described represents a practical design wherein various features of my invention are incorporated. While this combination of features have admirably fuliilled the objects of my invention it will be understood thatthese features may be employed singly or in combination, as desired, in various types of centrifugal governors and that the particular embodiment of my invention as herein shown and described is subject to many changes and modifications without departure from the scope of my invention, which I undertake to express according to the following claims.

I claim:

1. A resilient mounting for a flyweight of a centrifugal governor which is carried by a rotatable shaft, comprising a pair of supporting members mounted on said shaft for relative rectilinear movement therealong, a plurality of leaf springs connected at their end portions to said supporting members and at their central portions to said flyweight and each disposed parallel to the axis of said shaft; and spacing means clamped between said springs at their central and end portions for holding the springs spaced apart at said portions, the distance of spacing between the springs being at least a major fraction of the width of the springs.

2. In a centrifugal governor: including a rotatable supporting shaft and a iiyweight: a mounting for said yweight comprising a plurality of leaf springs arranged parallel to each other and disposed normal to the radius of said shaft, means clamping said springs together in fixed spaced relationship at their respective end portions and connecting said end portions to said shaft for relative movement, and means clamping the central portion of said springs together in fixed spaced relationship and securing the same to said flyweight, the distance of spacing between said springs bearing such relationship to the dimensions of said flyweight as substantially to restrict the movement of the flyweight to a translational 'motion in a direction radial of the shaft.

3. In a centrifugal governor: the combination of flyweights symmetrically disposed in relation to the shaft of the governor; a supporting means for each of said flyweights comprising a groupA of the flyweights along the radius of said shaft to effectively restrict the flyweights to a translational motion in a direction radial of the shaft.

4. In a centrifugal governor: the combination of a plurality of similar sector-shaped flyweights forming when in unoperated position a cylindrical structurer coaxially disposed in relation to the shaft of the governor; and resilient support# ing-'means for said respectiveyweights adapted to permitmovement of the iiyweights in translation in a .direction radial of said shaft While restricting the flyweights against other movements, comprising a pair of relatively movable members on `4saidshaft, a pair of overlying flat springs for thevflyweights respectively, the springs of said pairs" being radially' spaced and longitudinally disposed relative to said shaft and being conn'ected` at their ends'to said members and at theirv central portionsv tov their respective fly- Weght's, the central portion of.-each spring pair passing through its respective yweight; Vand means clamping the spring .pairs together in xed spaced relationship at the place of their connection 'tothe flyweights. 'i

`5. In a centrifugal governor?v thel combination of a flyweight; and a resilientbeam structure for supportingsaid flyweight comprising a group of leaf springs spaced from one another, a portion of said structure passing through said fly- Weight and being secured thereto in a relationship wherein said portion is symmetrically disposed With respect to the center of gravity of the flyweight.'

' MICHAEL J. vDI TORO. 

